Cm. Bulman et Ja. Koslow, DEVELOPMENT AND DEPTH DISTRIBUTION OF THE EGGS OF ORANGE ROUGHY, HOPLOSTETHUS-ATLANTICUS (PISCES, TRACHICHTHYIDAE), Marine and freshwater research, 46(4), 1995, pp. 697-705
The development of the eggs of deep-sea fish has seldom been described
. The eggs of orange roughy (Hoplostethus atlanticus), a mid-slope ben
thopelagic fish, were fertilized and incubated at three temperatures.
Those incubated at 7 degrees C hatched at 13 days; wild eggs were esti
mated to hatch at 7.3 days. Their development rate was similar to that
of eggs of fish from other orders and of shallower-living species. Fr
om depth-stratified plankton samples, early-stage eggs were found at 5
00-700 m. Their buoyancy was estimated to be 6.02 kg m(-3), the upper
end of the range of known fish-egg buoyancies. The eggs rose to the up
per mixed layer at an estimated 23.8 m h(-1), which is faster than asc
ent rates reported for other fishes. Their relative buoyancy and large
size would be the reason for this faster rate. However, large egg siz
e is apparently not an adaptation to enhance development rate; the mor
e rapid rise into warmer water reduces development time but does not f
ully compensate for the slower development.